若|2x+2y+3|+(xy-1)²=0,则x³+y³的值为
问题描述：
若|2x+2y+3|+(xy-1)²=0,则x³+y³的值为
答
2x+2y+3=0 且 xy-1=0
则,x+y=-3/2 ,xy=1
x³+y³
=(x+y)(x²-xy+y²)
=(x+y)[(x+y)²-3xy]
=-3/2 × [9/4-3]
=9/8